NFSD: Add "official" reviewers for this subsystem

At LFS 2023, it was suggested we should publicly document the name and
email of reviewers who new contributors can trust. This also gives them
some recognition for their work as reviewers.

Acked-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>